Many power tools, such as mills, drill presses, or miter saws, are capable of producing a cut or hole to a work piece placed against a horizontal table beneath a power drill or saw. Some power tools, such as miter saws, have a rotatable horizontal table for making vertical cuts to a work piece at various angles. A vertical cut made at such an angle is called a “miter cut”.
Some power tools, such as compound miter saws, have a capability for tilting a blade of the compound miter saw in a specific direction (usually, counter-clockwise) in order to make cuts at an acute angle to the vertical, generally from 0° to 45° (left of vertical for the user when facing the front end of the compound miter saw). A cut made with the blade tilted at an angle to the vertical (i.e., at a “bevel angle”) is called a “bevel cut”.
Still other power tools, such as dual bevel compound miter saws, have a capability for tilting the blade of the dual bevel compound miter saw both counter-clockwise and clockwise to an acute angle, generally from 0° to 45° either left or right of vertical. Dual bevel compound miter saws allow for a wider variety of bevel cuts by allowing the saw to tilt to a wider variety of bevel angles.
Bevel locking mechanisms are used to secure a tilted blade or drill at a particular bevel angle. There are conventional methods used for locking a tool at a particular bevel angle. However, there is a significant disadvantage to conventional methods in that conventional bevel locking systems have been generally located at the rear and of a cutting tool, away from a user. The user is thereby forced to reach over or behind the cutting tool in order to engage a bevel locking mechanism. The inaccessible location of conventional bevel locking mechanisms is both an inconvenience and a threat to user safety: these are significant disadvantages to heavy users of a conventional power tool, such as a miter saw.
U.S. Pat. No. 4,934,233 to Brundage et al. (“Brundage”) is representative of such prior art devices, disclosing an arrangement in which the miter angle for a cut may be adjusted using a handle located at the front of a compound miter saw (labeled 11 in FIG. 1 of Brundage). Adjustment of a bevel angle however, unlike that of the position of a cut, is accomplished through a bevel locking handle (labeled 27 in FIG. 2 of Brundage) located at the back of the compound miter saw. The bevel locking handle may be loosened to allow the upper blade and housing to be tilted about a bevel axis. After a bevel angle position has been selected, rotational movement of the bevel locking handle locks the saw at a particular bevel angle.
Also representative of the prior art is U.S. Pat. No. 5,235,889 to Brickner et al. (“Brickner”), which discloses a biasing system for locking a saw at a particular bevel angle for bevel cuts. In this biasing system, a handle (labeled 78 in FIG. 3 of Brickner) is provided, again at the rear of the device for locking the blade at a particular bevel angle. The handle system (shown in FIG. 7 of Brickner) uses a male and female conical taper structure, whereby the female structure is urged toward the male structure, eventually bringing the two into contact. As contact is established, the bevel angle is locked.
There is, therefore, a need for a bevel locking system whereby a user can change the bevel angle of a cutting tool with a mechanism disposed toward the front end of the tool.